I've been re-acquainting myself with flask after a number of months and found a couple of things in the docs that I felt could do with a fix.
I won't be offended if you think these are pointless changes and discard - but thought I'd submit a PR anyway...
Add closing html tag
Move docs explaining instantiating Flask
I'd swap the last two sentences.
Put the link to Flask class docs at the end.
@untitaker thanks for the feedback. I've made that change.